Hillary and Bill Clinton paid $3.2 million in federal income tax last year, a rate of 34.2 percent. Their 2015 return was released today by the Clinton campaign, almost five months after they signed it for filing.

The Clintons overpaid the Treasury and got a refund of more than $1 million.

The couple's income plunged last year. Adjusted gross income for 2015 was $10.6 million, compared with $27.9 million for the previous year. Charitable contributions accounted for 9.8 percent of their adjusted gross income.

Clinton is releasing the returns for two reasons: transparency and the opportunity to bash Donald Trump. The Republican nominee has refused to make his 2015 tax data public.

"Donald Trump is hiding behind fake excuses and backtracking on his previous promises," said Jennifer Palmieri, communications director for the Clinton campaign.

Trump and his lawyer have said the IRS is auditing his returns, so he can't or won't release them, although there is no legal prohibition on releasing returns that are being audited.

In a statement, Trump's campaign called the release of Clinton's tax return, "an attempt at distraction and misdirection" to take media attention off of Clinton's private email server.

The Clintons' tax documents depict a high-powered, high-income couple earning millions from speaking and consulting fees. They brought in $6.7 million from speeches, mostly his, and $3.1 million from book advances and royalties, almost entirely hers.

Bill Clinton also reported $1.7 million in consulting fees from two private education providers. Laureate Education paid him $1 million in 2015, for a total of $17.4 million since 2010, when Laureate's chairman first engaged him. Clinton resigned his position last year.

An investigative report by Bloomberg News found that while Bill Clinton was being paid by Laureate, the State Department under Hillary Clinton increased its grants to a nonprofit led by the chairman. Bloomberg reported that the Clinton campaign denied the allegation.

Also in 2010, Bill Clinton was appointed honorary chairman of a nonprofit associated with Gems Education, which is based in Dubai and operates mainly in the Middle East. He was paid $562,500 last year, in addition to $5.6 million in previous years.

In other income, Bill Clinton drew $226,297 in pensions as former president and former governor of Arkansas. The couple reported $109,290 in taxable interest and ordinary dividends. Their only Wall Street investment was a Vanguard 500 index fund.

Their charitable contributions were $42,000 to the Desert Classic Charities and $1 million to the Clinton Family Foundation, a vehicle for charitable giving that is not related to the high-profile Bill, Hillary and Chelsea Clinton Foundation.

The campaign released 10 years of returns for vice presidential nominee Tim Kaine and his wife, Anne Holton. Their 2015 adjusted gross income was $313,441, based almost entirely on their salaries — his as a U.S. senator from Virginia and hers as the state's secretary of education.

They paid $63,626 in federal taxes last year, for a tax rate of 20.3 percent. Their average federal tax rate for the past 10 years was 18 percent.

And here's one more revelation: Even though Hillary Clinton is asking voters to elect her to the nation's highest office, in IRS tax forms she's still just "spouse."